MaximS
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- Joined
- Jan 29, 2016
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Hi everyone!
A simple experiment was conducted by two Russian homebrewing microbiologists in a lab. Three cultures of microorganisms were prepared:
- Bacillus subtilis (gram-positive bacteria)
- Klebsiella spp (gram-negative)
- Candida Albicans (fungus)
The first part of the experiment was to test how effective StarSan and another local product called KatrilDes (won't focus on the latter) are as desinfectants in solutions when used in proportions recommended by manufacturers. In case of StarSan it is an ounce per 5 gallons*.
For testing the desinfectants were transfered to tubes and each was innoculated with 50 microliters of corresponding culture. After 20 minutes all them were moved to agar growth-medium plates. The sad results may be observed below (StarSan's part is marked as 'S')
As you can see desinfecting capabilities of StarSan (and the other desinfectant) are quite limited to say the least in the concentrations proposed by the manufacturer.
The second part of the experiment was to test whether the same products work as 6% solution (which is much more comparing to manufacturer's recommendations). The right part of the plate is 6% Hydrogen Peroxyde included as a control. The results are below (StarSan's part is marked as 'C' here)
In this concentration both products proved to be efficient desinfectants.
* Actually, guys misread the documentation and prepared one ounce per 5 litres, which is about 4 times stronger.
I expect a lot of comments stating something like 'I use StarSan and have 10/50/100 batches without contamination signs'. I found myself in pretty similar situation but using iodine-based sanitizer which proved absolutely useless in any reasonable concentrations being tested in similar conditions. So, I suppose it is really not that easy to infect a batch when you work clean, even when your sanitizer isn't that efficient.
Would be happy to hear if anyone conducted similar examination of desinfectants, especially StarSan, with different results.
P.S. All the content in guys' group is in Russian language but just in case here is the link https://vk.com/inquisitor_74,
A simple experiment was conducted by two Russian homebrewing microbiologists in a lab. Three cultures of microorganisms were prepared:
- Bacillus subtilis (gram-positive bacteria)
- Klebsiella spp (gram-negative)
- Candida Albicans (fungus)
The first part of the experiment was to test how effective StarSan and another local product called KatrilDes (won't focus on the latter) are as desinfectants in solutions when used in proportions recommended by manufacturers. In case of StarSan it is an ounce per 5 gallons*.
For testing the desinfectants were transfered to tubes and each was innoculated with 50 microliters of corresponding culture. After 20 minutes all them were moved to agar growth-medium plates. The sad results may be observed below (StarSan's part is marked as 'S')
As you can see desinfecting capabilities of StarSan (and the other desinfectant) are quite limited to say the least in the concentrations proposed by the manufacturer.
The second part of the experiment was to test whether the same products work as 6% solution (which is much more comparing to manufacturer's recommendations). The right part of the plate is 6% Hydrogen Peroxyde included as a control. The results are below (StarSan's part is marked as 'C' here)
In this concentration both products proved to be efficient desinfectants.
* Actually, guys misread the documentation and prepared one ounce per 5 litres, which is about 4 times stronger.
I expect a lot of comments stating something like 'I use StarSan and have 10/50/100 batches without contamination signs'. I found myself in pretty similar situation but using iodine-based sanitizer which proved absolutely useless in any reasonable concentrations being tested in similar conditions. So, I suppose it is really not that easy to infect a batch when you work clean, even when your sanitizer isn't that efficient.
Would be happy to hear if anyone conducted similar examination of desinfectants, especially StarSan, with different results.
P.S. All the content in guys' group is in Russian language but just in case here is the link https://vk.com/inquisitor_74,